This empty lot in Mission Bay off Third Street was purchased by the...

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Third and 16th Streets is the proposed site for the new Warriors Arena, in San Francisco.

Photo: Jason Henry, Special To The Chronicle

Third and 16th Streets is the proposed site for the new Warriors...

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Third and 16th Streets is the proposed site for the new Warriors Arena, in San Francisco.

Photo: Jason Henry, Special To The Chronicle

Third and 16th Streets is the proposed site for the new Warriors...

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Aerial view of where the Golden State Warriors proposed arena would have been located at Pier 30-32.

Photo: Warriors/Snohetta/steelblue

Aerial view of where the Golden State Warriors proposed arena would...

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A public plaza backed by a restaurant will replace what had been a high staircase and an entrance to a parking garage on the northwest corner of Piers 30-32. A gently sloping walkway flanked by shops and restaurants would lead up to the arena. The parking garage entrance was moved mid block. The plan also calls for a fire station and water taxi dock on that corner of the site.

Photo: Warriors/Snohetta/steelblue

A public plaza backed by a restaurant will replace what had been a...

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Hard-surfaced terraces facing south were replaced with sloping grass. The area would be part of 7.6 acres of public open space on the site.

Photo: Warriors/Snohetta/steelblue

Hard-surfaced terraces facing south were replaced with sloping...

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The Warriors were planning on building their new stadium at piers 30/32 in San Francisco.

Photo: Sonja Och, The Chronicle

The Warriors were planning on building their new stadium at piers...

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Seagulls congregate on Piers 30-32 in San Francisco. The site was preferred by the Golden State Warriors as a possible location for a new sports arena.

Photo: Paul Chinn, The Chronicle

Seagulls congregate on Piers 30-32 in San Francisco. The site was...

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The development that the owners of the Golden State Warriors which had wanted to build on Piers 30-32. The large circle is the proposed 18,000 seat area. The block on the inland side of the Embarcadero would include a hotel and a residential mid-rise.

Photo: Courtesy Golden State Warriors

The development that the owners of the Golden State Warriors...

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Red's Java House would have been moved south on the Embarcadero to make room for the new Golden State Warriors arena at Piers 30-32. Image courtesy the Warriors.

Red's Java House would have been moved south on the Embarcadero to...

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A rendition of the proposed Golden State Warriors arena at Piers 30-32. Courtesy the Golden State Warriors

A rendition of the proposed Golden State Warriors arena at Piers...

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In this file photo, Lawrence Stokus stops to talk to a security guard at Piers 30-32 about the proposed Warriors arena in San Francisco. Stokus lives in the neighborhood and would rather see the land be used as a park.

Photo: Sarah Rice, Special To The Chronicle

In this file photo, Lawrence Stokus stops to talk to a security...

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The new Golden State Warriors stadium site was formerly supposed to house the Salesforce Mission Bay Global Headquarters site.

Photo: Dwinslow, Courtesy Of The SF Planning Comm

The new Golden State Warriors stadium site was formerly supposed to...

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The new Golden State Warriors stadium site was formerly supposed to house the Salesforce Mission Bay Global Headquarters site.

Photo: Dwinslow, Courtesy Of The SF Planning Comm

The new Golden State Warriors stadium site was formerly supposed to...

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The new Golden State Warriors stadium site was formerly supposed to house the Salesforce Mission Bay Global Headquarters site.

Photo: Flad Architects

The new Golden State Warriors stadium site was formerly supposed to...

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The Golden State Warriors have purchased 12 acres in Mission Bay where Salesforce had planned to build a campus.

Abandoning their plan to build a new arena on Piers 30-32, The Golden State Warriors purchased a new area off thirds street in the Mission Bay district seen on on Monday April 21, 2014 in San Francisco, Calif.

Chain linked fence bends on 16th street between Third Street and Terry Francois Blvd. on Monday April 21, 2014 in San Francisco, Calif. where Salesforce plans construction on an entire block in the Mission Bay district

The Golden State Warriors have abandoned their plan to build an arena on Piers 30-32 just south of the Bay Bridge and instead have purchased a site in San Francisco's burgeoning Mission Bay to hold a new 18,000-seat venue.

The Warriors bought the 12-acre site from Salesforce.com at an undisclosed price in a deal signed Saturday night, said Rick Welts, the Warriors' president and chief operating officer. The team plans to have the arena ready for the 2018-19 NBA season.

The shift in location provides the Warriors with predictability and fewer regulatory hurdles. It also eliminates any need for voter approval, which may have become necessary for the Pier 30-32 venue that Mayor Ed Lee once called "my legacy project."

The change has assuaged some of the project's most vocal critics, who opposed building a 125-foot-high arena near the Embarcadero amid concerns about traffic, environmental harm during construction and blocked views of the Bay Bridge.

"To me, everybody wins here," Welts said. "We never lost sight of the overriding goal, which was to bring the Warriors to San Francisco and build this world-class sports and entertainment venue that the city has never had."

The Mission Bay site, where Salesforce once intended to build its corporate campus, has a Muni T-Third stop in front and has two adjacent parking garages that can hold a combined 2,130 cars. A new off-ramp from Interstate 280 will drop cars about two blocks away.

The site has street access on four sides, rather than only one side at Piers 30-32, easing pinch points. A waterfront park is planned across from the arena.

When the Central Subway opens - projected for 2019, the year after the Warriors plan to open the arena - the line will provide essentially a straight shot to the Powell Street Muni/BART Station downtown.

Private financing

The Warriors will own the site outright, rather than leasing it from the Port of San Francisco, and the team says the arena will be entirely privately financed - a rare instance of a modern sports venue that would use no taxpayer funds or public land.

The new site off Third Street does not, however, have the iconic feel and stunning views of the Bay Bridge. Instead, the view is of a dry dock, an industrial pier and rusting old pilings that dot the water. Visible across the bay are the cranes and skyline of Oakland, the Warriors' home after the team played in San Francisco from 1962 to 1971.

The Warriors' planned arena is part of a redevelopment area and growing biotech hub, with a UCSF Benioff Children's Hospital being built diagonally across from the arena site.

Lee and other officials see the arena as a catalyst for development in the neighborhood, a former rail yard that has little foot traffic at night, that will help as the city grows into the former industrial spaces on its southeast side, such as Pier 70 and the Hunters Point Shipyard.

"The mayor recognizes, and we recognize, that the city is moving south," Warriors co-owner Joe Lacob said. "There are some great advantages for the city in this as well."

Among them, construction on the parcel slated for the arena will trigger the creation of a 5.5-acre bayfront park, paid for by the master developer as part of the redevelopment plan for the area.

"This is a historic victory for the people of San Francisco because we have protected our precious bay and waterfront, as well as gained a new hometown basketball team," Agnos said.

The "process has worked," Peskin said. "San Francisco is going to have its cake and eat it too."

The Warriors have already spent about $20 million on design, engineering, consultants and other work for building on Piers 30-32. Some of that will transfer over, Welts said.

Impact on arena design

The interior of the arena will likely remain the same, although the exterior design could change to reflect the new surroundings, including possibly eliminating a public pedestrian walkway and lookout deck that had been planned for the previous site, Welts said. The arena will remain about the same height, 125 feet in the center - well below the 160-foot height limit for the property.

Whatever the final design, the arena will be a commanding presence, said Warriors co-owner Peter Guber.

"It has to be iconic, not just in design but in operation," Guber said.

The team has yet to decide what else it will seek to build on the 12-acre site, but Welts said it could include office space and retail geared toward arena visitors.

The site had been considered by the Warriors earlier but was ruled out as too expensive.

Salesforce bought 14 acres in Mission Bay in November 2010 to build its corporate campus. The San Francisco software giant announced in February 2012 that it was shelving its plan to build there.

The Warriors are buying a portion of the property - bounded by Terry Francois Boulevard and 16th, Third and South streets. UCSF is in advanced negotiations to buy another part of it.

The entire Salesforce site cost $248 million, but that figure doesn't include $23.3 million for "perpetual parking rights" in at least one nearby garage, or interest costs and property taxes since the purchase, according to a Salesforce filing with the Securities and Exchange Commission in November.

"The total carrying value of the land, building improvements and perpetual parking rights was $321.1 million" as of Oct. 31, according to the filing.

Costs of plan mounted

The Warriors would not disclose how much they paid for their 12-acre piece, but the site became more attractive after the cost to rebuild Pier 30-32 roughly doubled from the team's original projection two years ago to $180 million. When you add in the $40 million cost of building a terraced public park that had been planned to cover a parking garage on Piers 30-32, the team was looking at $220 million as a starting point, Lacob said.

"We paid a very pretty penny," Lacob said. "At the end of the day, you have to remember, it's important to envision something great for the city, for our fans, but it's also really important to get it done."

The specific location of an arena in the city is secondary, Lee said.

"The legacy for me," Lee said, "was getting the Warriors to come back to San Francisco."